The present invention relates generally to the art of separating glass sheets and relates more particularly to the art of applying powdered interleaving materials.
It is well-known in the art that stacked glass sheets may be protected from surface damage by the use of various interleaving material such as paper or powdered materials such as wood flour, polyethylene, polystyrene or polyacrylates. Powdered materials are preferably finely divided, fairly uniform in size distribution, and free-flowing so that they may be applied by means of conventional, commercially available equipment.
U.S. Pat. No. 3,723,312 to Hay discloses using a dedusted agglomerated salicylic acid, mixed with an inert separator material such as polystyrene beads. This particulate interleaving material may be applied to glass by mechanical dusters or other particulate application equipment known to those skilled in the art of dusting glass with wood flour or other inert particulate interleaving materials.
U.S. Pat. No. 4,200,670 to Albach describes a method of treating glass sheets to be stacked by applying water, a stain inhibiting material such as ammonium chloride, and dry particles of a mechanical separator such as wood flour, to such sheets in a plurality of sequential steps. According to one specific embodiment, the water and stain inhibitor are first applied to the glass as an aqueous solution of the latter to provide a wet layer on the sheet surface, and then separately applying a dry particulate layer of a mechanical separator is specifically applied to the wet layer. The method can also be carried out by first spraying the glass surface with water alone, and then separately applying or layers of a stain inhibitor and a mechanical separator in dry powdered form to the layer of water; or by first applying a layer of a mixture of dry powdered stain inhibitor and mechanical separator and then spraying this layer of dry material with water.